934925ad04eb268c8fe0d58d993e4cb0b3a19775
1 /**
2 * \file object-snapper.cpp
3 * \brief Snapping things to objects.
4 *
5 * Authors:
6 * Carl Hetherington <inkscape@carlh.net>
7 * Diederik van Lierop <mail@diedenrezi.nl>
8 *
9 * Copyright (C) 2005 - 2008 Authors
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include "libnr/n-art-bpath.h"
15 #include "libnr/nr-path.h"
16 #include "libnr/nr-rect-ops.h"
17 #include "libnr/nr-point-fns.h"
18 #include "live_effects/n-art-bpath-2geom.h"
19 #include "2geom/path-intersection.h"
20 #include "document.h"
21 #include "sp-namedview.h"
22 #include "sp-image.h"
23 #include "sp-item-group.h"
24 #include "sp-item.h"
25 #include "sp-use.h"
26 #include "display/curve.h"
27 #include "desktop.h"
28 #include "inkscape.h"
29 #include "prefs-utils.h"
30 #include "sp-text.h"
31 #include "sp-flowtext.h"
32 #include "text-editing.h"
34 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
35 : Snapper(nv, d), _snap_to_itemnode(true), _snap_to_itempath(true),
36 _snap_to_bboxnode(true), _snap_to_bboxpath(true), _strict_snapping(true),
37 _snap_to_page_border(false), _include_item_center(false)
38 {
39 _candidates = new std::vector<SPItem*>;
40 _points_to_snap_to = new std::vector<NR::Point>;
41 _bpaths_to_snap_to = new std::vector<NArtBpath*>;
42 _paths_to_snap_to = new std::vector<Path*>;
43 }
45 Inkscape::ObjectSnapper::~ObjectSnapper()
46 {
47 _candidates->clear(); //Don't delete the candidates themselves, as these are not ours!
48 delete _candidates;
50 _points_to_snap_to->clear();
51 delete _points_to_snap_to;
53 _clear_paths();
54 delete _paths_to_snap_to;
55 delete _bpaths_to_snap_to;
56 }
58 /**
59 * Find all items within snapping range.
60 * \param r Pointer to the current document
61 * \param it List of items to ignore
62 * \param first_point If true then this point is the first one from a whole bunch of points
63 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
64 * \param DimensionToSnap Snap in X, Y, or both directions.
65 */
67 void Inkscape::ObjectSnapper::_findCandidates(SPObject* r,
68 std::list<SPItem const *> const &it,
69 bool const &first_point,
70 std::vector<NR::Point> &points_to_snap,
71 DimensionToSnap const snap_dim) const
72 {
73 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
74 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
75 bool const c3 = points_to_snap.size() == 0;
77 if (!(c1 || c2) || c3) {
78 return;
79 }
81 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
83 if (first_point) {
84 _candidates->clear();
85 }
87 NR::Maybe<NR::Rect> bbox = NR::Rect(); // a default NR::Rect is infinitely large
88 NR::Coord t = getSnapperTolerance();
90 // When dragging a guide...
91 NR::Point p_guide = points_to_snap[0];
92 if (!getSnapperAlwaysSnap()) {
93 bbox = NR::Rect(p_guide, p_guide); // bbox is now just a single point: p_guide
94 bbox->growBy(t); // bbox width and height now measure 2x snapper tolerance
95 // for angled guidelines the bbox is now larger than really needed
96 // (up to sqrt(2) for 45 deg. guidelines) but we'll leave it like that
97 } // else: use an infinitely large bbox to find candidates
99 for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
100 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
102 /* See if this item is on the ignore list */
103 std::list<SPItem const *>::const_iterator i = it.begin();
104 while (i != it.end() && *i != o) {
105 i++;
106 }
108 if (i == it.end()) {
109 /* See if the item is within range */
110 if (SP_IS_GROUP(o)) {
111 _findCandidates(o, it, false, points_to_snap, snap_dim);
112 } else {
113 // Now let's see if any of the snapping points is within snapping range of this object
114 if (snap_dim == TRANSL_SNAP_XY) {
115 bbox = sp_item_bbox_desktop(SP_ITEM(o));
116 } // else: we're snapping a guide to an object and we will use the bbox as defined above
118 if (bbox) {
119 for (std::vector<NR::Point>::const_iterator i = points_to_snap.begin(); i != points_to_snap.end(); i++) {
120 NR::Point b_min = bbox->min();
121 NR::Point b_max = bbox->max();
122 bool withinX = ((*i)[NR::X] >= b_min[NR::X] - t) && ((*i)[NR::X] <= b_max[NR::X] + t);
123 bool withinY = ((*i)[NR::Y] >= b_min[NR::Y] - t) && ((*i)[NR::Y] <= b_max[NR::Y] + t);
124 if (withinX && withinY) {
125 //We've found a point that is within snapping range
126 //of this object, so record it as a candidate
127 _candidates->push_back(SP_ITEM(o));
128 break;
129 }
130 }
131 }
132 }
133 }
134 }
135 }
136 }
139 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
140 bool const &first_point) const
141 {
142 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
143 // e.g. when translating an item using the selector tool, then we will only do this for the
144 // first point and store the collection for later use. This significantly improves the performance
145 if (first_point) {
146 _points_to_snap_to->clear();
148 // Determine the type of bounding box we should snap to
149 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
151 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
152 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
153 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
155 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
156 g_assert(!(p_is_a_node && p_is_a_bbox || p_is_a_bbox && p_is_a_guide || p_is_a_node && p_is_a_guide));
158 if (_snap_to_bboxnode) {
159 gchar const *prefs_bbox = prefs_get_string_attribute("tools", "bounding_box");
160 bbox_type = (prefs_bbox != NULL && strcmp(prefs_bbox, "geometric")==0)? SPItem::GEOMETRIC_BBOX : SPItem::APPROXIMATE_BBOX;
161 }
163 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
164 //NR::Matrix i2doc(NR::identity());
165 SPItem *root_item = *i;
166 if (SP_IS_USE(*i)) {
167 root_item = sp_use_root(SP_USE(*i));
168 }
169 g_return_if_fail(root_item);
171 //Collect all nodes so we can snap to them
172 if (_snap_to_itemnode) {
173 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
174 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_points_to_snap_to));
175 }
176 }
178 //Collect the bounding box's corners so we can snap to them
179 if (_snap_to_bboxnode) {
180 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
181 NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
182 if (b) {
183 for ( unsigned k = 0 ; k < 4 ; k++ ) {
184 _points_to_snap_to->push_back(b->corner(k));
185 }
186 }
187 }
188 }
189 }
190 }
191 }
193 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
194 Inkscape::Snapper::PointType const &t,
195 NR::Point const &p,
196 bool const &first_point,
197 std::vector<NR::Point> *unselected_nodes) const
198 {
199 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
201 _collectNodes(t, first_point);
203 if (unselected_nodes != NULL) {
204 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
205 }
207 SnappedPoint s;
208 bool success = false;
210 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
211 NR::Coord dist = NR::L2(*k - p);
212 if (dist < getSnapperTolerance() && dist < s.getDistance()) {
213 s = SnappedPoint(*k, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
214 success = true;
215 }
216 }
218 if (success) {
219 sc.points.push_back(s);
220 }
221 }
223 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
224 Inkscape::Snapper::PointType const &t,
225 NR::Point const &p,
226 NR::Point const &guide_normal) const
227 {
228 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
229 _collectNodes(t, true);
231 SnappedPoint s;
232 bool success = false;
234 NR::Coord tol = getSnapperTolerance();
236 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
237 // Project each node (*k) on the guide line (running through point p)
238 NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
239 NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
240 NR::Coord dist2 = NR::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
241 if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
242 s = SnappedPoint(*k, dist, tol, getSnapperAlwaysSnap());
243 success = true;
244 }
245 }
247 if (success) {
248 sc.points.push_back(s);
249 }
250 }
252 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
253 bool const &first_point,
254 SPPath const *selected_path,
255 NArtBpath *border_bpath) const
256 {
257 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
258 // e.g. when translating an item using the selector tool, then we will only do this for the
259 // first point and store the collection for later use. This significantly improves the performance
260 if (first_point) {
261 _clear_paths();
263 // Determine the type of bounding box we should snap to
264 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
266 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
268 if (_snap_to_bboxpath) {
269 gchar const *prefs_bbox = prefs_get_string_attribute("tools", "bounding_box");
270 bbox_type = (prefs_bbox != NULL && strcmp(prefs_bbox, "geometric")==0)? SPItem::GEOMETRIC_BBOX : SPItem::APPROXIMATE_BBOX;
271 }
273 // Consider the page border for snapping
274 if (border_bpath != NULL) {
275 _bpaths_to_snap_to->push_back(border_bpath);
276 }
278 /* While editing a path in the node tool, findCandidates must ignore that path because
279 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
280 * This path must not be ignored however when snapping to the paths, so we add it here
281 * manually when applicable.
282 *
283 * It must be the last one in the list, as this is assumption is being used in _snapPaths()
284 */
285 if (_snap_to_itempath && selected_path != NULL) {
286 _candidates->push_back(SP_ITEM(selected_path));
287 }
289 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
291 /* Transform the requested snap point to this item's coordinates */
292 NR::Matrix i2doc(NR::identity());
293 SPItem *root_item = NULL;
294 /* We might have a clone at hand, so make sure we get the root item */
295 if (SP_IS_USE(*i)) {
296 i2doc = sp_use_get_root_transform(SP_USE(*i));
297 root_item = sp_use_root(SP_USE(*i));
298 g_return_if_fail(root_item);
299 } else {
300 i2doc = sp_item_i2doc_affine(*i);
301 root_item = *i;
302 }
304 //Build a list of all paths considered for snapping to
306 //Add the item's path to snap to
307 if (_snap_to_itempath) {
308 if (!(_strict_snapping && !p_is_a_node)) {
309 // Snapping to the path of characters is very cool, but for a large
310 // chunk of text this will take ages! So limit snapping to text paths
311 // containing max. 240 characters. Snapping the bbox will not be affected
312 bool very_lenghty_prose = false;
313 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
314 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
315 }
316 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
317 // which corresponds to a lag of 500 msec. This is for snapping a rect
318 // to a single line of text.
320 // Snapping for example to a traced bitmap is also very stressing for
321 // the CPU, so we'll only snap to paths having no more than 500 nodes
322 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
323 bool very_complex_path = false;
324 if (SP_IS_PATH(root_item)) {
325 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
326 }
328 if (!very_lenghty_prose && !very_complex_path) {
329 SPCurve *curve = curve_for_item(root_item);
330 if (curve) {
331 NArtBpath *bpath = bpath_for_curve(root_item, curve, true, true);
332 _bpaths_to_snap_to->push_back(bpath);
333 // Because we set doTransformation to true in bpath_for_curve, we
334 // will get a dupe of the path, which must be freed at some point
335 sp_curve_unref(curve);
336 }
337 }
338 }
339 }
341 //Add the item's bounding box to snap to
342 if (_snap_to_bboxpath) {
343 if (!(_strict_snapping && p_is_a_node)) {
344 NRRect rect;
345 sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
346 NArtBpath *bpath = nr_path_from_rect(rect);
347 _bpaths_to_snap_to->push_back(bpath);
348 }
349 }
350 }
351 }
352 }
354 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
355 Inkscape::Snapper::PointType const &t,
356 NR::Point const &p,
357 bool const &first_point,
358 std::vector<NR::Point> *unselected_nodes,
359 SPPath const *selected_path,
360 NArtBpath *border_bpath) const
361 {
362 _collectPaths(t, first_point, selected_path, border_bpath);
364 // Now we can finally do the real snapping, using the paths collected above
365 SnappedPoint s;
366 bool success = false;
368 /* FIXME: this seems like a hack. Perhaps Snappers should be
369 ** in SPDesktop rather than SPNamedView?
370 */
371 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
372 NR::Point const p_doc = desktop->dt2doc(p);
374 // Convert all bpaths to Paths, because here we really must have Paths
375 // (whereas in _snapPathsConstrained we will use the original bpaths)
376 if (first_point) {
377 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
378 Path *path = bpath_to_Path(*k);
379 if (path) {
380 path->ConvertWithBackData(0.01); //This is extremely time consuming!
381 _paths_to_snap_to->push_back(path);
382 }
383 }
384 }
386 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
387 if (*k) {
388 bool being_edited = false; // True if the current path is being edited in the node tool
389 if (unselected_nodes != NULL) {
390 if (unselected_nodes->size() > 0 && selected_path != NULL) { // If the node tool is active ...
391 if (*k == _paths_to_snap_to->back()) { // and we arrived at the last path in the vector ...
392 being_edited = true; // then this path is currently being edited
393 }
394 }
395 }
397 for (unsigned i = 1 ; i < (*k)->pts.size() ; i++) {
398 NR::Point start_point;
399 NR::Point end_point;
400 NR::Maybe<Path::cut_position> o = NR::Nothing();
401 if (being_edited) {
402 /* If the path is being edited, then we will try to snap to each piece of the
403 * path individually. We should only snap though to stationary pieces of the paths
404 * and not to the pieces that are being dragged around. This way we avoid
405 * self-snapping. For this we check whether the nodes at both ends of the current
406 * piece are unselected; if they are then this piece must be stationary
407 */
408 (*k)->PointAt(i, 0, start_point);
409 (*k)->PointAt(i, 1, end_point);
410 start_point = desktop->doc2dt(start_point);
411 end_point = desktop->doc2dt(end_point);
412 g_assert(unselected_nodes != NULL);
413 bool c1 = isUnselectedNode(start_point, unselected_nodes);
414 bool c2 = isUnselectedNode(end_point, unselected_nodes);
415 if (c1 && c2) {
416 o = get_nearest_position_on_Path(*k, p_doc, i);
417 }
418 } else {
419 /* If the path is NOT being edited, then we will try to snap to the path as a
420 * whole, so we need to do this only once and we will break out at the end of
421 * this for-loop iteration */
422 /* Look for the nearest position on this SPItem to our snap point */
423 o = get_nearest_position_on_Path(*k, p_doc);
424 (*k)->PointAt(o->piece, 0, start_point);
425 (*k)->PointAt(o->piece, 1, end_point);
426 start_point = desktop->doc2dt(start_point);
427 end_point = desktop->doc2dt(end_point);
428 }
430 if (o && o->t >= 0 && o->t <= 1) {
431 /* Convert the nearest point back to desktop coordinates */
432 NR::Point const o_it = get_point_on_Path(*k, o->piece, o->t);
433 NR::Point const o_dt = desktop->doc2dt(o_it);
434 NR::Coord const dist = NR::L2(o_dt - p);
436 if (dist < getSnapperTolerance()) {
437 // if we snap to a straight line segment (within a path), then return this line segment
438 if ((*k)->IsLineSegment(o->piece)) {
439 sc.lines.push_back(Inkscape::SnappedLineSegment(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), start_point, end_point));
440 } else {
441 // for segments other than straight lines of a path, we'll return just the closest snapped point
442 if (dist < s.getDistance()) {
443 s = SnappedPoint(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
444 success = true;
445 }
446 }
447 }
448 }
450 // If the path is NOT being edited, then we will try to snap to the path as a whole
451 // so we need to do this only once
452 if (!being_edited) break;
453 }
454 }
455 }
457 if (success) {
458 sc.points.push_back(s);
459 }
460 }
462 /* Returns true if point is coincident with one of the unselected nodes */
463 bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
464 {
465 if (unselected_nodes == NULL) {
466 return false;
467 }
469 if (unselected_nodes->size() == 0) {
470 return false;
471 }
473 for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
474 if (NR::L2(point - *i) < 1e-4) {
475 return true;
476 }
477 }
479 return false;
480 }
482 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
483 Inkscape::Snapper::PointType const &t,
484 NR::Point const &p,
485 bool const &first_point,
486 ConstraintLine const &c) const
487 {
489 // Consider the page's border for snapping to
490 NArtBpath *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
492 _collectPaths(t, first_point, NULL, border_bpath);
494 // Now we can finally do the real snapping, using the paths collected above
496 /* FIXME: this seems like a hack. Perhaps Snappers should be
497 ** in SPDesktop rather than SPNamedView?
498 */
499 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
500 NR::Point const p_doc = desktop->dt2doc(p);
502 NR::Point direction_vector = c.getDirection();
503 if (!is_zero(direction_vector)) {
504 direction_vector = NR::unit_vector(direction_vector);
505 }
507 NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
508 NR::Point const p2_on_cl = p1_on_cl + direction_vector;
510 // The intersection point of the constraint line with any path,
511 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
512 // The distance between those points is twice the snapping tolerance
513 NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
514 NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
515 NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
517 Geom::Path cl;
518 cl.start(p_min_on_cl.to_2geom());
519 cl.appendNew<Geom::LineSegment>(p_max_on_cl.to_2geom());
521 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
522 if (*k) {
523 // convert a Path object (see src/livarot/Path.h) to a 2geom's path object (see 2geom/path.h)
524 // TODO: (Diederik) Only do this once for the first point, needs some storage of pointers in a member variable
525 std::vector<Geom::Path> path_2geom = BPath_to_2GeomPath(*k);
527 for (std::vector<Geom::Path>::const_iterator l = path_2geom.begin(); l != path_2geom.end(); l++) {
528 Geom::SimpleCrosser sxr;
529 Geom::Crossings crossings = sxr.crossings(*l, cl);
530 for (std::vector<Geom::Crossing>::const_iterator m = crossings.begin(); m != crossings.end(); m++) {
531 // Reconstruct the point of intersection
532 NR::Point p_inters = p_min_on_cl + ((*m).tb) * (p_max_on_cl - p_min_on_cl);
533 // When it's within snapping range, then return it
534 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < tb < 1)
535 if ((*m).tb >= 0 && (*m).tb <= 1 ) {
536 NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
537 SnappedPoint s(desktop->doc2dt(p_inters), dist, getSnapperTolerance(), getSnapperAlwaysSnap());
538 sc.points.push_back(s);
539 }
540 }
541 }
542 }
543 }
544 }
547 void Inkscape::ObjectSnapper::_doFreeSnap(SnappedConstraints &sc,
548 Inkscape::Snapper::PointType const &t,
549 NR::Point const &p,
550 bool const &first_point,
551 std::vector<NR::Point> &points_to_snap,
552 std::list<SPItem const *> const &it,
553 std::vector<NR::Point> *unselected_nodes) const
554 {
555 if ( NULL == _named_view ) {
556 return;
557 }
559 /* Get a list of all the SPItems that we will try to snap to */
560 if (first_point) {
561 _findCandidates(sp_document_root(_named_view->document), it, first_point, points_to_snap, TRANSL_SNAP_XY);
562 }
564 if (_snap_to_itemnode || _snap_to_bboxnode) {
565 _snapNodes(sc, t, p, first_point, unselected_nodes);
566 }
568 // Consider the page's border for snapping to
569 NArtBpath *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
571 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
572 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
573 if (n > 0) {
574 /* While editing a path in the node tool, findCandidates must ignore that path because
575 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
576 * That path must not be ignored however when snapping to the paths, so we add it here
577 * manually when applicable
578 */
579 g_assert(it.size() == 1);
580 g_assert(SP_IS_PATH(*it.begin()));
581 _snapPaths(sc, t, p, first_point, unselected_nodes, SP_PATH(*it.begin()), border_bpath);
583 } else {
584 _snapPaths(sc, t, p, first_point, NULL, NULL, border_bpath);
585 }
586 }
587 }
589 void Inkscape::ObjectSnapper::_doConstrainedSnap( SnappedConstraints &sc,
590 Inkscape::Snapper::PointType const &t,
591 NR::Point const &p,
592 bool const &first_point,
593 std::vector<NR::Point> &points_to_snap,
594 ConstraintLine const &c,
595 std::list<SPItem const *> const &it) const
596 {
597 if ( NULL == _named_view ) {
598 return;
599 }
601 /* Get a list of all the SPItems that we will try to snap to */
602 if (first_point) {
603 _findCandidates(sp_document_root(_named_view->document), it, first_point, points_to_snap, TRANSL_SNAP_XY);
604 }
606 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
607 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
608 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
610 // When snapping to objects, we either snap to their nodes or their paths. It is however very
611 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
612 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
613 // so we will more or less snap to them anyhow.
615 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
616 _snapPathsConstrained(sc, t, p, first_point, c);
617 }
618 }
621 // This method is used to snap a guide to nodes, while dragging the guide around
622 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
623 NR::Point const &p,
624 NR::Point const &guide_normal) const
625 {
626 if ( NULL == _named_view ) {
627 return;
628 }
630 /* Get a list of all the SPItems that we will try to snap to */
631 std::vector<SPItem*> cand;
632 std::list<SPItem const *> const it; //just an empty list
634 std::vector<NR::Point> points_to_snap;
635 points_to_snap.push_back(p);
637 DimensionToSnap snap_dim;
638 if (guide_normal == component_vectors[NR::Y]) {
639 snap_dim = GUIDE_TRANSL_SNAP_Y;
640 } else if (guide_normal == component_vectors[NR::X]) {
641 snap_dim = GUIDE_TRANSL_SNAP_X;
642 } else {
643 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
644 }
645 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
647 // It would be cool to allow the user to rotate a guide by dragging it, instead of
648 // only translating it. (For example when CTRL is pressed). We will need an UI part
649 // for that first; and some important usability choices need to be made:
650 // E.g. which point should be used for pivoting? A previously snapped point,
651 // or a transformation center (which can be moved after clicking for the
652 // second time on an object; but should this point then be constrained to the
653 // line, or can it be located anywhere?)
655 _findCandidates(sp_document_root(_named_view->document), it, true, points_to_snap, snap_dim);
656 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
658 // _snapRotatingGuideToNodes has not been implemented yet.
659 }
661 /**
662 * \return true if this Snapper will snap at least one kind of point.
663 */
664 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
665 {
666 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
667 return (_snap_enabled && _snap_from != 0 && snap_to_something);
668 }
670 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
671 {
672 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
673 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
674 }
676 void Inkscape::ObjectSnapper::_clear_paths() const
677 {
678 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
679 g_free(*k);
680 }
681 _bpaths_to_snap_to->clear();
683 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
684 delete *k;
685 }
686 _paths_to_snap_to->clear();
687 }
689 NArtBpath* Inkscape::ObjectSnapper::_getBorderBPath() const
690 {
691 NArtBpath *border_bpath = NULL;
692 NR::Rect const border_rect = NR::Rect(NR::Point(0,0), NR::Point(sp_document_width(_named_view->document),sp_document_height(_named_view->document)));
693 SPCurve const *border_curve = sp_curve_new_from_rect(border_rect);
694 if (border_curve) {
695 border_bpath = SP_CURVE_BPATH(border_curve);
696 }
698 return border_bpath;
699 }
700 /*
701 Local Variables:
702 mode:c++
703 c-file-style:"stroustrup"
704 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
705 indent-tabs-mode:nil
706 fill-column:99
707 End:
708 */
709 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :